The long-term goal of this project is to determine how a signal originating at the cell periphery triggers a series of events culminating in the synthesis and assembly of an intracellular organelle. Specifically, we are studying the mechanisms by which deciliation of the ciliated protozoan Tetrahymena thermophila initiates the orderly expression of specific genes required for reformation of cilia. Improved methods have been developed for obtaining viable deciliation of Tetrahymena which induces a rapid (approximately l0-fold) induction of protein synthesis and a specific, relative (approximately l0-fold) co-ordinate induction of alpha and beta tubulins. Translational and transcriptional mechanisms underlying this general induction of protein synthesis and specific induction of tubulin are being examined. Polysomal polyA ion RNA isolated from regenerating cells 80-l00 min. after deciliation (at which time tubulin represents approximately l0% of total protein synthesis) is being utilized as a source of cDNA from which tubulin gene sequences will be prepared by recombinant DNA techniques. These cloned DNA sequences will then be utilized to study the organization of tubulin genes and their expression during regeneration.